Means for polishing multifocal lenses



L. W. BUGBEE.

MEANS FOR POLISHING MULTIFOCAL LENSES.

APPLICATION FILED MAR. 13, 1920.

Patented Nov. 15, 1921.

2 SHEETS-SHEET I.

IN VEN TOR.

Zz/cM/v M 606555.

A TTORNEY- L. W. BUGBEE.

MEANS FOR POLISHING MULTIFOCAL LENSES.

APPLICATION FILED MAR. 13, 1920.

1,397,399, Patented Nov. 15, 1921.

2 SHEETS-SHEET 2.

JNVENTOR. lac/,4 M 506556 ATTORNEY LUCIAN W. BUGBEE, OF INDIANAPOLIS, INDIANA, ASSIGNOR 'IO ONEPIECE ."BIFOCAL LENS COMPANY, OF INDIANAPOLIS, INDIANA, A CORPORATION.

:nnansron ronrsnrne Monrrrociar, Lenses.

Specification of Letters Patent. Patented NQV, 15, 1921.,

Application filed. March 13, 1920. Serial No. 365,460."

To all w 71cm. it may concern:

Be it known that L LUCIAN W. BUGBEE, a citizen of the United States, and a resident of Indianapolis, county of Marion, and State of Indiana, have invented a certainnew and useful Means for Polishing Multifocal Lenses; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, in which like numerals refer to like parts.

The object of this invention is the improvement in the polishing of the surfaces ofbifocal lenses and it relates particularly to means for simultaneously polishing the distance and reading surfaces of bifocal lenses by independent polishing buttons or tools for said surfaces so as to polish'said surfaces uniformly and perfectly.

The chief feature of the invention consists in providing holding means for said plurality of polishing. buttons or tools which will keep the sameoperating ontheirrespective surfaces and accurately positioned so as to polish the surfaces throughout their areas evenly andup tothe line of division between the surfaces and exert a pressure on the polishing buttons approximately in proportion to their sizes so as to cause the polishing thereof.

Heretofore in the practice in the manufacture of such lenses the two surfaces'have been successively polished by independent means, at least where accurate polishing and optically perfect bifocal lenses were desired. This invention is to do such work simultaneously and yet perfectly and attain as nearly as possible the ideal of equivalent treatment of both surfaces.

The full'nature of the invention will be understood from the accompanying drawings and the following description and claims:

In the drawings, Figure 1 is a side elevation of a portion of a lens'polishing machine including thisinvention. Fig. 2 is a plan view of what is shown in Fig. 1. Fig. 3 is a vertical sectional view' through parts of the machine showing the lens blank: and holder in central vertical section, the remaining parts being in front elevation and partially broken away. Fig. L is a plan view of the lens blank shown in Fig. 3 and the polishing buttons thereon. Fig. 5 is a plan view of the blank after it has been polished, the lines on which it is out to form the final completed lenses being indicated by dotted lines. Fig. 6 is a section on the line 66 of Fig. 3. Fig. 7 is a section on the; line 7-7 of Fig. 3. i

There are shown in Figs. 1 and 2 parts of a machine in connection with which this inventlon has been and can beused, although mostparts of the machine are old. There is shown atable 10 with avertical. shaft 11 mounted in the bearings 12, said shaft carrying a removable lens holder 13 ofcommon type on which a target lens blank 14: is se= cured for treatment. The shaft 11 is driven by means of a pulley 15 and belt 16. On said table there is a base plate 110 carrying stationary bearing posts 17 carrying bearlngs 18 in which bearing screws 19 are horizontally mounted, as shown in Fig. 2,.in connection with whichthe arm or frame 20 is pivoted at its rear end and its front end 1s acted upon by gravity for exerting pressure on the polishing means or buttons. The gravity can be'increased byadding additional weights, not shown as is often done in the practice.

In Fig. 3 there is shown a front elevation of the frontend of the armQO which has a segmental-shaped plate 24 rigid therewith. The clamping plate 25 is associated with the plate 24- for clamping a rod 26 in proper position. Bolts 27 secure the plate 25 in position and one of these bolts extends through a slot 28in the plate 24 so that the angular position of the clamping plate-25 may be adjusted in order. to-hold the rod 26 in proper inclination. a

The bifocallens blank 14 as shown'inFig. 3 is secured on the, lens holder 13 and has a central area 30, which is the reading surface of the lens blank, and the surrounding an nular area 31, which is the distance surface of the lens blank. These two surfaces appear in Fig. 4E, and are there shown separated by a'division line32, although in the actual lens said division line is practically invisible. For polishing the central or reading surface 30 a small button 35 is used and for polishing the surrounding surface 31 a larger button 36 isused. The small button has a diameter equal to one-half. of the diameter of the reading surface 30 and the large polishing button has adiameter equal to the width of the distance surface 31 between the edge of the blank and the reading surface. Said blank is what is known in the trade as a target'lens bifocal blank. Said two surfaces have been genthe polishing buttons 35 and 36 are held in .7

place by pins 37' and 38, respectively, ar-

ranged so at to permit the'polishing but? tons to revolve on the lens blank as they 7 may be caused to revolve by the rotation of the blank. Thisusual'ly gives sufficient rev: olution of the buttons to causethe desired cross rubbing, as the buttons will rotate sub stantially at the speed of the lens blankat its line of contact with the polishing button farthest from .the center of the lens blank. ,The pins 37 and 38 are Securedin a bar 40 pivoted by a pin .il-to the lower end of the rod 26. This enables the bar 40 to rock and permit the p'olishingbuttons to fully engage and accommodate themselves to the surfaces of the blank during'the polishing operation, andthe weight of the arm 20, rod 26, bar 4:0 and pins 37 and 38'will be constantly exerted on the polishingv buttons in order'to cause the friction desired for the polishing action; 'In order to cause'an equivalent polishing action by the two buttons, the bar 10 is provided with a number of holes 42 so that it can be properly pivoted to effect said result. To this end the bearing pin 41 should be located ata point near the pin 38 of the larger button, for since the large button has two or three times the polishing surface of thesmall button, there should come to it through thepin 38 proportionately. more pressure. Therefore, the distances between the pivot 41 and the pins 37 and 38should bes'ubstantia'lly in reverse ratio to the diameters of the'buttons.

Since the relative distances of travel on the len blank of the outer and inner edges of the large'button 36 are not relatively great, the outer portion of said buttondoes not always rotate with the blankLa-nd it is desirable for that button to always rotate to effect cross polishing. Therefore, the two buttons areconnected by a belt 50 in grooves 51' so that the smallbutton will always cause the large button totrotate. Since the glass blank under the outer edge of the small button travels infinitely faster than the portion under the inner edge of the smallbutton, which is at the center of the lens blank, the lens blank always causes the outer portion of the inner button to rotate in the same direction as the blank.

In order to accommodate the rocking pin frame to buttons of varying diameters or to lens blanksof varying dimensions, the pins 40 through which the shank of the pin extends and it isscrew threaded and a nut 61 on the upper end clamps the pin in adjusted position.

The invention claimed is: V 1. Means for-simultaneously pollshlng a plurality of concentric surfaces of lens blanks including a polishing button for each surface, a pin frame having a pin for loosely engaging each button, and vertically movable means to which said pin, frame is pivoted between the pins so the pin frame can rock thereon vertically.

2. :The combination with a lens holder for holding a lens blank having a, plurality of concentric surfaces to be polished, and means for rotating the same,of a polishing button.

for each surface thereof, a pin frame having a pin for looselyengaging each button, and vertically movable means to which said pin frame is pivoted between the pins so the pin frame can rock thereon vertically.

.3. The combination with a rotary lens holder adapted to hold. a. lens blank having a central portion and a surrounding annular portion, of a polishing button for the surrounding annular portion with 'a diameter substantially the same as the width of said surrounding portion, a polishing button of a smaller size for the inner portion having a diameter substantially one-half of said portion, a pin frame with a pin engaging each .of said buttons and. arranged so as to hold the button for the inner portion be This is illustrated in Fig. 6,

the outer portion between the inner and outer peripheriesof saidportion, and vertically movable 'means to which said pin frame is pivoted betweenthepins so that it can rock vertically. a

1. Means for polishing simultaneously the surfaces of a lens blank having a central circular surface and a surrounding annular surface, including a small polishing button for the central surface and a larger polishing button for the surrounding surface, a

pin frame having substantially-parallel pins secured therein for engaging and holding the buttons on the respective surfaces of the lens, and vertically movable. means to which said pin frame is pivoted between the pins at a point nearer the pin for the large button than the pin for the small button in order to equalize more nearly the polishing action of the buttons.

5. Means for polishing simultaneously the surfaces of a lens blank having a central circular surface and a surrounding annular surface, including a polishing button for the central surface and another "polishing button for the surrounding surface, a pin for engaging and holding each button in place, a bar to which said pins are secured which has a series of pivot holes in it, and vertically movable means pivotally connected with said bar in one of said pivot holes.

6. Means for polishing simultaneously the surfaces of a lens blank having a central circular surface and a surrounding annular surface, including a polishing button for the central surface and another polishing button for the surrounding surface, a pin for engaging and holding each button in place, a bar in which said pins are mounted, means for adjustably mounting the pins in said bar so that the pins can be adjusted toward or away from each other, and vertically movable means to which said bar is pivoted between said pins. 7

7. Means for simultaneously polishing a plurality of concentric surfaces of lenses including a polishing button for each surface adapted to have free rotation, a single mechanism for holding them in position on said surfaces but permitting independent vertical. movement of the buttons, and a belt connecting said buttons so that one button the other central surface and a surface surrounding said central surface, and means for rotating said lens holder, of a button for polishing each of said surfaces, means for holding said buttonsin place so they can rotate and polish said lens blank surfaces simultaneously, and a belt connecting said buttons so one will influence the rotation of the other.

9. Means for polishing simultaneously the surfaces of a lens blank having a central circular surface and a surrounding annular surface, including a small polishing button for the central surface and a larger button for the surrounding surface, a pin frame having a pin for engaging and holding each of said polishing buttons, vertically movable means to which said pin frame is pivoted between said pins, and a belt connecting saidbuttons for enabling the smaller button to control the rotation of the large button.

In witness whereof, I have hereunto affixed my signature.

. LUCIAN W. BUGBEE. 

